Enables protein tyrosine kinase activator activity and signaling adaptor activity. Acts upstream of or within megakaryocyte development; plasma membrane bounded cell projection morphogenesis; and somitogenesis. Located in lamellipodium and neuron projection. Part of SCAR complex. Is expressed in several structures, including alimentary system; brain; eye; genitourinary system; and hemolymphoid system gland. Orthologous to human ABI1 (abl interactor 1). [provided by Alliance of Genome Resources, Apr 2022]